Arrangement of valves and passages in the cylinders of steam-engines



E. D. BARRETT. 1 1 VALVE MOVEMENT FOR STEAM ENGINES.

No 19,119. Patented Jan. 19, 1858.

UNITED STATES PATENT OFFICE.

E. D. BARRETT, OF CINCINNATI, OHIO.

ARRANGEMENT OF VALVES AND PASSAGES IN THE CYLINDERS OF STEAM-ENGINES.

Specification of Letters Patent No. 19,119, dated January 19, 1858.

To all whom it may concern Be it known that I, EDWARD D. BARRETT, ofCincinnati, Hamilton county, Ohio, have invented a new and usefulArrangement of Valves and Passages in the Cylinders of Steam-Engines;and I hereby declare the following to be a full and exact description ofthe same, reference being had to the accompanying drawings, making partof this specification.

My invention relates to an arrangement of valves and passages in thecylinders of steam engines, for cushioning the piston and aiding inreversing its stroke.

In the accompanying drawings Figure l is an axial section through thecylinder and valve chambers. Fig. 2 represents the auxiliary port andvalve on an enlarged scale.

A, is a steam cylinder, having piston P, slide valve B, exhaust C, andside passages D, D,- all of customary form except that the passages D,D, instead of issuing at the extremities of the cylinder are a littleless than the length of the piston therefrom.

E, E, are two auxiliary passages, fed from the former at certain periodsof the stroke, through valve guarded ports 6, e, and dischargingrespectively at the extreme ends of the interior space of the cylinder.

F, is a rocker arm operated by a tappet G, on the piston rod E. Thisarmin the present illustrationoperates on the main valve B, through theagency of an auxiliary slide valve 6, and cylinder at, provided with adouble headed piston 20, p, and operating in connection with a set ofpassages similar to those of the main cylinder. The main valve B, isattached to the small piston rod 1", midway between the two heads p, p.This auxiliary cylinder and its appendages may be dispensed with ifpreferred.

The valve which closes the port 6, or e, is constructed as follows :Thevalve proper consists of a cup formed piece I, having a cap J, piercedby a stem K, which is retained within the cap by a foot L. The stem K,is screw threaded (M), so as to fit a corresponding hollow screw in thecase. The upper part of this stem emerges through a stuffing box N, andterminates in a knob or handle 0. By means of this screw threaded stemthe range of the valve I, may be restricted or wholly stopped at will orthe valve may be permanently held more or less open.

The tappet, rocker arm, slide valves and piston are so arrangedrelatively to each other and to the steam and exhaust passages, that theinstant the main piston P, has passed (for example) the side passage D,at the (then) exhaust end of the cylinder, the small slide valve 7), isdrawn back by the rocker arm to the position indicated in the drawing,which, by reversing the steam in the small cylinder, shoots the mainslide valve B, to the position shown, so as to connect the side passageD with the exhaust and the side passage D with the steam; but the pistonhaving just closed the vent of this passage, the steam flows by thevalve I, into the auxiliary passage E, and the space 1, in front of thepiston until an equilibrium is established when, the valve I, closingthe steam thus confined, cushions the piston and aids in reversing itsmotion. lVhen the piston has passed the side passage D, in its returnstroke, it receives steam therefrom and the same motions are repeated atthe other end of the cylinder. It will be observed that this arrangementdoes not obstruct the freedom of the exhaust, the back of the pistonbeing relieved from all but atmospheric pressure at the instant that thesteam cushion becomes effective on the other side.

The principal aim of this invention is to transfer the momentum from theend of each stroke of the piston to the beginning of the next, thusavoiding concussion, insuring the prompt return of the piston andenabling it to pass the dead points without a balance wheel, whereby itis made applicable to the working of pumps and other purposes where asimple reciprocating movement only is required, but novelty is claimedonly in the specific means here employed, as I am aware that variousmodes of effecting the above objects have been heretofore proposed.

I claim as new and of my invention herein:

The arrangement of check valves I, I, and passages E, E, in relation tothe passages D, D, and the main valve substantially as herein set forth.

In testimony of which invention I hereunto set my hand.

E. D. BARRETT.

Attest:

GEO. I-I. KNIGHT, J. B. BENNETT.

